Khan Academy (English - US curriculum)
Math by grade
Eureka Math/EngageNY
Precalculus (Eureka Math/EngageNY)
Module 5: Probability and statistics
Topic A: Lesson 4: Using permutations and combinations to compute probabilities
Exactly three heads in five flips
Exactly three heads in five flips
Probability of exactly 3 heads in 5 flips using combinations
License: CC BY-NC-SA by Khan Academy